FIELD OF THE INVENTION
The operation of many of the switches that are in service and have a hinge, blade and jaw contacts, is such that when the switch starts to open, the tail of the blade which makes contact in the jaw, has to turn 90.degree. before it begins to open and this is lost time. Then the blade opens in a radius, which is time consuming, and this operation is made through the medium of an operating pipe which is connected to the interphase linkage, with more lost time.
In an electrical circuit, switches of all types and designs are used by private industries and electric utility companies for different operating needs and requirements. Switches are used manually to remove from service sections of electrical circuits and equipment when its services are no longer needed, or taken out of service for maintenance work. Switches are also used to operate automatically either for a routine type of operation where the mode of operation commands it or under predetermined fault conditions where a relay or sensor detects a malfunction of either the operation, or electrical fault where it is essential to detect and remove an electrical circuit or equipment from the electrical system as soon as possible to limit the damage to the circuit or equipment which would be caused by the high current flow to ground. Also by the quick detection and removal from service of any electrically faulted component of an electrical circuit or system it creates a more stable system. When electrical faults occur, the current flow increases and the voltage decreases, which is a very unstable condition, and this undesirable unstable condition burdens down the circuits by the high amplitude of fault current and also the low voltage places a burden on all types of rotary electrical equipment.
In the clearing from service of an electrical circuit, or piece of equipment, it is necessary to have a visible break or gap between the source of electricity and the circuit, or equipment, to be worked upon for safety reasons so that there is no doubt that the circuit or equipment is deenergized and can be worked upon safely.
In many cases in private industry and in the electrical utility companies, the electrical switches used to remove from service, either by design or by fault conditions, an electrical circuit or equipment is called an "oil circuit breaker." An oil circuit breaker is constructed so that the contacts which open to deenergize an electrical circuit or equipment are immersed in a tank of oil. These contacts are not visible and to provide the necessary visible break or gap for safety reasons, a switch consisting of a hinge, blade and jaw is also used in series with the oil circuit breaker.
The design and the operation of the present arrow switch takes into consideration all of the aforementioned conditions. It can be operated manually by the means of an operating pipe, electrically by pushing an open-close button, can be programmed by relaying or sensors to operate for specific operations, can be operated by relays automatically when an abnormally high flow of current is detected by the current transformer in an electrical circuit and when opened and locked open gives the safety requirements needed to work on electrical circuits or equipment.
The desin and operation of the arrow switch is radically new and different from the types in use today. It is constructed so that the close-open operations are completed with a straight line thrust of the blade from the blade guide to the jaw contact (close position), or the jaw contact to the blade guide (open position). This operation can be computed mathematically and with no lost time due to the operating pipe inter-phase linkage, operating in a straight line, no lost time due to a radius, and no need for the blade to turn to seat properly. This complete operation of the arrow switch is much faster when computed electrically in cycles (60 cycles per second) and in operating to clear an electrical fault time is the most important factor.
The need for the arrow switch design and operation in today's electrical utility systems is much desired and timely because of the complexity of these systems (mainly the 34.5 KV distribution systems) the mode of operation, the cost of the arrow switch versus the accepted practice in the industry of using an oil circuit breaker and a visible break switch to accomplish the same operation and safety clearance.
The insulation value and current carrying capability of the arrow switch is not limited to any set voltage or current carrying capabilities. The arrow switch would be constructed using existing proven materials and to the specifications set forth by the National Electrical Manufacturing Association, which sets the standards for the electrical utilities, nation wide.
The method of operating either manually, electrically or automatically would be dictated by the operation requirements. The basic arrow switch can be modified to incorporate any and/or all the options, such as manual or electromagnetic mode of closing and opening of the arrow switch, potential and current transformers for detection of loss of voltage and/or fault current for automatically sectionalizing of circuits and which can be programmed to open to clear transient or lightening faults and then reclose automatically after a predetermined period of time (time delay).
The arrow switch can fulfill a void which now exists in the operation of an electrical system by being comparably inexpensive to existing equipment now in use, versatile in its application to an electrical system and make some electrical systems more stable where fuses are now used to detect and clear faults and when fuses blow, circuits remain out of service until the fuses have been replaced.